Composition, alignment layer and method for preparing same, liquid crystal alignment unit and liquid crystal display panel

Abstract

The invention belongs to the technical field of displaying, and provides a composition, an alignment layer and a method for preparing the same, a liquid crystal (LC) alignment unit and a liquid crystal display panel. The invention can solve the problems existing in the prior methods for achieving of multi-domain display of LC display devices, such as complex manufacturing processes, high cost, difficult to be manufactured. The composition (alignment layer) of the present invention allows adjusting the alignment of the molecules in the surface of the resultant coating layer of the composition, through adjusting the contents of the components in the composition, the polymerization temperature, and/or the thickness of the coating of the composition. The alignment layer, the LC alignment unit, and the LC display panel according to the invention can be prepared using a simple process and allow to achieve a multi-domain display at a lower cost.

The invention claimed is: 
     
       1. A composition, characterized in that, the composition comprises a binaphthol-based chiral compound and a smectic liquid crystal polymerizable monomer. 
     
     
       2. The composition according to  claim 1 , characterized in that, said smectic liquid crystal polymerizable monomer is 2-methylbutyl 4′-(4-(6-(acryloxy)hexyloxy)benzoyloxy)biphenyl-4-carboxylate. 
     
     
       3. The composition according to  claim 1 , characterized in that, said binaphthol-based chiral compound is 1,1′-(4′-(2-methylbutyl) biphenyl) binaphthol ester. 
     
     
       4. The composition according to  claim 1 , characterized in that, said composition further comprises a photoinitiator; wherein said smectic liquid crystal polymerizable monomer and said binaphthol-based chiral compound in the composition respectively have a mass fraction of x, y; and said photoinitiator in the composition has a mass fraction of 0.05x; and wherein x and y satisfy the following formula:
   1.05 x+y= 1, wherein  y  is between 0.04 and 0.15. 
 
     
     
       5. The composition according to  claim 4 , characterized in that, said photoinitiator is benzil dimethyl ketal. 
     
     
       6. An alignment layer, characterized in that, said alignment layer is prepared by polymerizing a composition, wherein said composition comprises a binaphthol-based chiral compound and a smectic liquid crystal polymerizable monomer. 
     
     
       7. A method for preparing an alignment layer, characterized in that, said method comprises the following steps:
 1) mixing, in which a smectic liquid crystal polymerizable monomer, a binaphthol-based chiral compound, and a photoinitiator are mixed together in a predetermined ratio to form a composition; 
 2) coating, in which said composition is coated onto a substrate to form a coating film of the composition; and 
 3) polymerization reaction, in which said coating film of the composition is irradiated with UV light at a predetermined temperature to initiate polymerization of said smectic liquid crystal polymerizable monomer therein to produce a smectic liquid crystal polymer. 
 
     
     
       8. The method according to  claim 7 , characterized in that, said predetermined ratio is such that said smectic liquid crystal polymerizable monomer and said binaphthol-based chiral compound in the composition respectively have a mass fraction of x, y; and said photoinitiator in the composition has a mass fraction of 0.05x; wherein x and y satisfy the following formula:
   1.05 x+y= 1, wherein  y  is between 0.04 and 0.15. 
 
     
     
       9. The method according to  claim 7 , characterized in that, said predetermined temperature is a temperature within ±3° C. of the smectic-cholesteric phase transition temperature of said composition, or any temperature at which said composition is in a cholesteric phase. 
     
     
       10. A liquid crystal alignment unit, characterized in that, said liquid crystal alignment unit comprises a first alignment layer, said first alignment layer being prepared by polymerizing a composition comprising a binaphthol-based chiral compound and a smectic liquid crystal polymerizable monomer. 
     
     
       11. The liquid crystal alignment unit according to  claim 10 , characterized in that, said first alignment layer comprises a plurality of alignment regions, wherein adjacent alignment regions differ in alignment direction. 
     
     
       12. The liquid crystal alignment unit according to  claim 10 , characterized in that,
 said first alignment layer includes alignment regions separated from each other; 
 said liquid crystal alignment unit further comprises a second alignment layer, wherein said first alignment layer is provided on said second alignment layer, and said second alignment layer has an alignment direction different from that of said alignment regions of the first alignment layer. 
 
     
     
       13. A liquid crystal display panel, characterized in that, the liquid crystal display panel comprises an array substrate, a color filter substrate and a liquid crystal layer disposed therebetween, wherein a liquid crystal alignment unit is provided on the side of the array substrate and/or the color filter substrate in contact with the liquid crystal layer, wherein said liquid crystal alignment unit comprises a first alignment layer, said first alignment layer being prepared by polymerizing a composition comprising a binaphthol-based chiral compound and a smectic liquid crystal polymerizable monomer. 
     
     
       14. The liquid crystal display panel according to  claim 13 , characterized in that, said first alignment layer comprises a plurality of alignment regions, wherein adjacent alignment regions differ in alignment direction. 
     
     
       15. The liquid crystal display panel according to  claim 13 , characterized in that,
 said first alignment layer includes alignment regions separated from each other; 
 said liquid crystal alignment unit further comprises a second alignment layer, wherein said first alignment layer is provided on said second alignment layer, and said second alignment layer has an alignment direction different from that of said alignment regions of the first alignment layer. 
 
     
     
       16. The liquid crystal display panel according to  claim 13 , characterized in that, said smectic liquid crystal polymerizable monomer is 2-methylbutyl 4′-(4-(6-(acryloxy)hexyloxy)benzoyloxy)biphenyl-4-carboxylate. 
     
     
       17. The liquid crystal display panel according to  claim 13 , characterized in that, said binaphthol-based chiral compound is 1,1′-(4′-(2-methylbutyl) biphenyl) binaphthol ester. 
     
     
       18. The liquid crystal display panel according to  claim 13 , characterized in that, said composition further comprises a photoinitiator; wherein said smectic liquid crystal polymerizable monomer and said binaphthol-based chiral compound in the composition respectively have a mass fraction of x, y; and said photoinitiator in the composition has a mass fraction of 0.05x; and wherein x and y satisfy the following formula:
   1.05 x+y= 1, wherein  y  is between 0.04 and 0.15.